1. Field of the Invention
This invention relates to the production of petroleum from a petroleum-containing subterranean formation employing an aqueous driving fluid containing, as a thickening agent, a biopolymer synthesized by an alga and to the synthesis of the biopolymer by an alga such as Porphyridium aerugineum.
2. Description of the Prior Art
Processes for the production of petroleum from a petroleum-containing subterranean formation employing an aqueous driving fluid containing a thickening agent is well known. U.S. Pat. No. 3,020,207 discloses such a process where the thickening agent is a heteropolysaccharide that has been reacted with an aldehyde, the heteropolysaccharide being a fermentation product produced by the action of bacteria of the genus Xanthomonas upon a carbohydrate. U.S. Pat. No. 3,352,358 discloses a process employing thickened aqueous driving fluid where the thickening agent is polyvinyl alcohol sulfate. U.S. Pat. No. 3,372,749 also discloses a process employing thickened aqueous driving fluid where the thickening agent is a poly(glucosylglucan). In the process disclosed in U.S. Pat. No. 3,373,810, the thickening agent for the aqueous driving fluid is sulfoalkylated poly(glucosylglucan), a sulfoalkylated polysaccharide or a mixture of both, the polysaccharide being the heteropolysaccharide produced by the action of the bacterium Xanthomonas campestris on glucose.
Procedures for the growth of algae are also well known. For example, U.S. Pat. No. 3,195,271 discloses a process for the growth of the alga Porphyridium cruentum. This patent also discloses the synthesis of the alga constituent, carrageenin, and discloses that the liquid phase of the culture in which the alga is grown is viscous or mucilaginous. Procedures for the growth of alga are also disclosed in "Algal Culture: From Laboratory to Pilot Plant", J. S. Burlew, Ed., Carnegie Inst. of Washington, Publication No. 600, Washington, D. C. (1964), and "Properties and Products of Algae", J. S. Zajic, Ed., Plenum Press, N. Y. (1970). It is also well known that many marine and fresh water species of alga liberate synthesis products into their surroundings that have drag reducing properties, Hoyt, J. W., and Soli, G., Science, 149, 1509 (1965). The influence of light quality on the production of algal biomass production is disclosed in "Spectral Light Requirements of Algae", Brown, T. E., Tech. Report No. 69-45-FL, U.S. Army Natick Labs., October, 1968.